Synthesis of 1,4-Diketones via Titanium-Mediated Reductive Homocoupling of α-Haloketones

1,4-Diketones have been synthesized via a reductive homocoupling of α-haloketones. Addition of a Grignard reagent to titanium(IV) isopropoxide affords a low-valent titanium(III) intermediate that is believed to mediate a radical dimerization reaction. The reaction works well for a variety of aromatic α-haloketones including heteroaromatic compounds.